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Least squares means (LSM) of traits by packaging treatment for pork chops and ground pork stored at 1°C

 
Traits1 Control FreshCase SEM P-value
Pork chops
Lean L* 47.58a 46.75b 0.25 0.017
Lean a* −1.47b 0.71a 0.08 <0.0001
Lean b* 6.23a 5.83b 0.10 0.007
Fat L* 68.48a 67.77b 0.18 0.007
Fat a* 0.44b 1.18a 0.08 <0.0001
Fat b* 10.85a 9.93b 0.14 <0.0001
APB 5.41 5.26 0.06 0.088
LAB 5.49 5.41 0.06 0.325
pH 5.74 5.75 0.01 0.501
TBARS 0.27b 0.33a 0.01 0.0002
Ground Pork
L* 47.79 47.50 0.27 0.453
a* 6.05b 6.69a 0.08 <0.0001
b* 14.59 14.65 0.12 0.727
APB 6.03 5.98 0.03 0.202
LAB 5.98 5.94 0.03 0.252
pH 6.25b 6.28a 0.01 0.005
a,bLSM with different superscripts within row are different at P < 0.05.
1L* reflects the lightness of meat color, a* reflects the redness, and b* reflects the yellowness. APB: aerobic psychrotrophic bacteria; LAB: lactic acid bacteria; TBARS: thiobarbituric acid reactive substance.



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The effect of storage time (phase) on instrumental color (least squares means; CIE L*, a*, b*) of pork chops stored at 1°C1

 
Lean3
Fat3
Phase2 L* a* b* L* a* b*
Phase 1 45.89b (0.66) −0.34a (0.17) 5.62b (0.22) 68.34b (0.69) 0.33b (0.17) 9.48b (0.33)
Phase 2 49.03a (0.38) −0.82b (0.1) 5.74b (0.13) 71.21a (0.4) 0.6b (0.1) 10.18a (0.19)
Phase 3 46.16b (0.32) −0.08a (0.08) 6.33a (0.1) 65.94c (0.33) 1.07a (0.08) 10.75a (0.16)
a–cMeans with different superscript within columns are different at P < 0.05
1SE are given in parentheses.
2Phases are grouped on the basis of aerobic psychrotrophic bacteria plate count cutoff (log cfu/g). Phase 1: d 0 to 10 (<2 log cfu/g); phase 2: d 15 to 37 (2 to 6 log cfu/g); phase 3: d 38 to 50 (>6 log cfu/g).
3L* reflects the lightness of meat color, a* reflects the redness, and b* reflects the yellowness.



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Least square means (LSM) of bacterial counts (log cfu/g) for pork chops stored in different packaging types during storage time (day) at 1°C1

 
APB2
LAB2
Day Control FreshCase Average Control FreshCase Average
0 1.33 1.74 1.53n 1.49 1.63 1.56l
5 1.25 1.41 1.33n 1.15 1.35 1.25l
10 1.86 1.26 1.56n 1.29 1.16 1.22l
15 2.59 2.23 2.41n 2.42 2.39 2.41k
20 3.63 3.04 3.33m 3.49 3.70 3.6j
25 5.13 4.46 4.79k 5.29 4.66 4.97i
28 5.05 4.38 4.71k 5.14 4.75 4.94i
30 5.53 4.50 5.01j,k 5.63 4.91 5.27h,i
32 5.04 5.83 5.44h,i,j 4.87 6.03 5.45h,i
34 5.12 5.36 5.24i,j,k 5.15 5.46 5.31h,i
36 5.80 6.14 5.97e,f,g,h 6.30 6.34 6.32e,f
37 5.81 5.73 5.77g,h,i 5.97 5.44 5.7g,h
38 6.29 5.80 6.05e,f,g 6.31 5.96 6.13f,g
39 6.40 5.71 6.05e,f,g 6.84 6.13 6.49d,e,f
40 6.81 6.04 6.52c,d,e 6.87 6.33 6.6c,d,e,f
41 6.45 6.59 6.42c,d,e,f 6.90 6.52 6.71b,c,d,e
42 6.37 6.39 6.38c,d,e,f,g 6.63 6.93 6.78b,c,d,e
43 6.06 6.46 6.26d,e,f 6.19 6.69 6.44d,e,f
44 6.32 6.78 6.55c,d,e 6.36 6.88 6.62c,d,e,f
45 6.50 6.54 6.52c,d,e 6.61 6.55 6.58d,e,f
46 7.12 6.67 6.9b,c 7.20 6.74 6.97b,c,d
47 6.86 7.07 6.97a,b,c 6.98 7.30 7.14a,b,c
48 7.14 6.53 6.83b,c,d 7.23 6.68 6.95b,c,d
49 7.30 7.15 7.23a,b 7.43 7.12 7.27a,b
50 7.40 7.61 7.5a 7.51 7.66 7.58a
SEM 0.27 0.34 0.23 0.26 0.30 0.21
a–nLSM with different superscript letters within columns differ (P < 0.05).
1Since there was no interactive effect between storage time and packaging type, only day effect on the average counts of bacteria from samples stored in Control and FreshCase packages is reported.
2Aerobic psychrotrophic bacteria (APB) grew on tryptic soy agar plates (Acumedia, Neogen Corp, Lansing, MI) that were incubated at 7°C for 10 d; lactic acid bacteria (LAB) grew on de Man, Rogosa, and Sharpe agar plates (Lactobacilli MRS Agar; Difco Laboratories, Inc.,Detroit, MI) that were incubated at 25°C for 5 d.



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Least squares means (LSM) of odor panel scores by storage time (phase) effect for raw and cooked pork chops stored at 1°C1

 
Raw
Cooked
Phase2 Putrid Acidic Sour Rancid Meaty Putrid Acidic Sour Rancid Meaty
Phase 1 0.1b (0.05) 0c (0.00) 0.06b (0.02) 0.08c (0.05) 4.56 (0.12) 0.07c (0.04) 0.18b (0.11) 0.02c (0.01) 0.07c (0.04) 8.93a (0.24)
Phase 2 1.63a (0.17) 0.43b (0.07) 1.55a (0.12) 1.14b (0.14) 4.31 (0.15) 0.53b (0.10) 0.51a (0.10) 0.39b (0.08) 1.30b (0.23) 7.26c (0.22)
Phase 3 1.68a (0.14) 0.81a (0.09) 2.03a (0.12) 1.83a (0.13) 4.27 (0.10) 1.04a (0.14) 0.53a (0.10) 0.66a (0.08) 2.49a (0.15) 7.95b (0.14)
a–cLSM with different superscripts within columns are different at P < 0.05.
1Panel scores were measured as the distance of a marked vertical line from the extreme left end of a 15-cm scale. The extreme left indicated no presence, and the extreme right indicated a very strong presence. SE are given in parentheses.
2Phases are grouped on the basis of aerobic psychrotrophic bacteria plate count cutoff (log cfu/g). Phase 1: d 0 to 10 (<2 log cfu/g); phase 2: d 15 to 37 (2 to 6 log cfu/g); phase 3: d 38 to 50 (>6 log cfu/g).



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The effect of storage time on instrumental color (least squares means; CIE L*, a*, b*) of ground pork sausages stored at 1°C1

 
Day L* a* b*
0 44.62e 5.39g 13.24d
5 45.89d,e 6.66b,c,d 13.50d
10 46.59d 5.62f,g 12.19e
13 44.82d,e 6.09e,f 14.51c
15 58.70a 6.53c,d,e 16.64a
17 46.57d 7.28a 14.84b,c
19 49.25c 6.26de 15.32b
20 44.99d,e 7.17ab 14.48c
21 52.99b 6.95a,b,c 16.55a
22 45.51d,e 6.03e,f 14.95b,c
23 44.17e 6.10e,f 14.66b,c
SEM 0.64 0.18 0.28
a–gLeast squares means with different superscripts within a column are different at P < 0.05.
1L* reflects the lightness of meat color, a* reflects the redness, and b* reflects the yellowness.



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Least squares means (LSM) of bacterial counts (log cfu/g) for ground pork sausages stored in different packaging types during storage time (day) at 1°C

 
APB1
LAB1
Day Control FreshCase Average2 Control FreshCase Average2
0 2.47 2.48 3.42h 3.41 3.43 2.48i
5 3.24 3.08 3.36i 3.42 3.29 3.16h
10 4.57 4.72 4.63h 4.51 4.75 4.65g
13 5.48 5.31 5.39g 5.46 5.32 5.40f
15 6.29 5.87 6.01f 6.20 5.81 6.08e
17 6.62 6.65 6.57e 6.56 6.57 6.63d
19 7.07 7.02 6.84d 6.87 6.82 7.04c
20 7.22 7.16 7.14c 7.15 7.13 7.19c
21 7.35 7.63 7.37b 7.32 7.42 7.49b
22 7.69 7.59 7.62a 7.66 7.59 7.64a,b
23 7.80 7.80 7.69a 7.74 7.63 7.80a
SEM 0.09 0.08 0.06 0.08 0.1 0.06
a–iLSM with different superscript letters within columns differ (P < 0.05).
1Aerobic psychrotrophic bacteria (APB) grew on tryptic soy agar plates (Acumedia, Neogen Corp, Lansing, MI) that were incubated at 7°C for 10 d; lactic acid bacteria (LAB) grew on de Man, Rogosa, and Sharpe agar plates (Lactobacilli MRS Agar; Difco Laboratories, Inc.,Detroit, MI) that were incubated at 25°C for 5 d.
2Since there was no interactive effect between storage time and packaging type, only day effect on the average counts of bacteria from samples stored in Control and FreshCase packages is reported.



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Least squares means of odor panel scores by storage time (phase) for raw and cooked pork sausages stored at 1°C1

 
Raw
Cooked
Phase2 Putrid Acidic Sour Rancid Meaty Putrid Acidic Sour Rancid Meaty
Phase 1 0c (0.0) 0.08c (0.04) 0c (0.00) 0.09b (0.06) 6.61a,b (0.80) 0b (0.00) 0b (0.00) 0.03b (0.03) 0b (0.00) 7.84b (0.34)
Phase 2 0.09b (0.04) 0.51b (0.12) 0.43b (0.12) 0.54a (0.08) 7.17a (0.21) 0.11a (0.05) 0.15a,b (0.07) 0.28a (0.09) 0.54a (0.12) 9.13a (0.26)
Phase 3 0.40a (0.11) 1.12a (0.10) 1.31a (0.10) 0.73a (0.08) 5.87b (0.17) 0.16a,b (0.08) 0.22a (0.09) 0.20a,b (0.09) 0.71a (0.10) 8.66a,b (0.26)
a–cMeans with different superscript within columns are different at P < 0.05.
1Panel scores were measured as the distance of a marked vertical line from the extreme left end of a 15-cm scale. The extreme left indicated no presence, and the extreme right indicated a very strong presence of the odor attributes. SE are given in parentheses.
2Phases are grouped on the basis of aerobic psychrotrophic bacteria plate count cutoff (log cfu/g). Phase 1: d 0 to 5 (<3 log cfu/g); phase 2: day 10 to 19 (2 to 7 log cfu/g); phase 3: d 20 to 23 (>7 log cfu/g).



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Least squares means (LSM) of thiobarbituric acid reactive substances (TBARS) values for pork sausage affected by packaging × storage time (day) stored at 1°C1

 
Day
Packaging 0 5 10 13 15 17 19 20
Control 0.34b,c,d 0.21e,f,g 0.33b,c,d,e 0.20e,f,g 0.23d,e,fg 0.18f,g 0.35b,c 0.32b,c,d,e
FreshCase 0.27c,d,e,f,g 0.24c,d,e,f,g 0.25c,d,e,f,g 0.29b,c,d,e,f,g 0.30b,c,d,e,f 0.17g 0.36b,c 0.55a
a–gLSM with the different superscript are different at P < 0.05
1The SEM for the test is 0.04.